The objectives of the present project are to analyze in detail the receptive field characteristics of neurons in rabbit visual system and to describe normal and abnormal development of these cells. It is proposed to study the following topics: (1) Visual receptive fields in brain regions outside the visual projection system in adult rabbit; (2) normal developmental sequence of neurons in the ventral nucleus of lateral geniculate body, lateroposterior-pulvinar complex, and pretectal areas; (3) abnormal development of visual cells following visual deprivation or neonatal ablation of visual structures; (4) any abnormal cell morphology in the striate cortex of deprived animals as revealed by light or electron-microscopy; (5) any effects on receptive fields following iontophoretic injections of bicuculline, GABA, glutamate, etc; (6) any correlation between receptive field types and cell morphologyy in horseradish peroxidase injected material; (7) any correspondence between retinal fiber groups to lateral geniculate cell groups; (8) the response properties of interneurons in lateral geniculate body; and (9) the functional significance, if any, of receptive field types, relating to visuallyy guided behavior.